How photo realistic was the ray tracing done by the yorkfield cpu? Theres various degrees if I understood the article right. It has to of course deliver graphics better then current software/hardware can. The cpu managed to make an image in realtime, using ray-tracing at a resolution of 768*768, right? If so, that's very promising I guess. If it scales 100%, 2 yorkfields could do 1280*1024 at slightly lower FPS.
Not sure if what draggoon sais is right though. From what I understood a pixel will be 'updated' if a ray hits something or doesn't hit something. When more objects appear in a scene, more pixels will have to be updated, esepecially because of reflections and such?